Report of isolated epidural extra-nodal Rosai-Dorfman disease of cervicothoracic spine.

Introduction: Rosai-Dorfman disease (RDD) or sinus histiocytosis with massive lymphadenopathy is a nonneoplastic lymphoproliferative disorder which commonly presents with painless massive cervical lymphadenopathy along with fever and weight loss. Isolated extra-nodal disease involvement, especially isolated central nervous system disease without lymph node involvement is rare.

Case Presentation: A 35-year-old man presented with upper back pain and paraparesis of 2 months duration. Contrast-MRI revealed an enhancing epidural mass lesion from C6-T7 suggestive of a primary epidural spinal-cord tumor. The lesion was resected and posterolateral fusion C6-T8 was performed. Histopathological examination revealed an isolated extra-nodal case of RDD. He was started on chemotherapy after the healing of surgical site in 2 weeks post operatively. Complete resolution of neurological deficits with significant improvement in gait was seen at the last follow-up 2 years after surgery. Repeat MRI revealed complete resolution of the disease.

Discussion: RDD with spinal involvement is rare and it is often a challenge to arrive at the correct diagnosis. Histopathological characteristics and immunohistochemical findings are necessary for diagnosis. Resection of the lesion takes compression off the cord and therefore, is the primary line of management of this disease. Our case presentation serves as a reference when diagnosing and managing a patient of RDD.